The present invention relates to an apparatus for three-phase (i.e., solid/liquid/gas) separation during treatment of wastewater and sludge, having a gas collector, positioned in a settling basin, for capturing the gas arising during the conversion process in the apparatus for three-phase separation or gas introduced therein, the gas collector having an outer surface which allows sewage sludge to slide off and which is slanted in relation to the horizontal.
Such an apparatus for three-phase separation is used for the purpose of capturing, in the gas collector, the fermentation gases arising during the aerobic or anaerobic conversion process or the gases supplied during aerobic treatment. These gases are then available, in the first case cited, as an energy source for a further use, to operate the apparatus or even for other purposes, or, in the second case cited, for odor removal, for example.
For this purpose, it is known to construct the gas collector with an angular form in such a way that it has two legs which form the slanted outer surface and simultaneously enclose a volume, into which the gas may flow unhindered from underneath. The sewage sludge introduced from above slides essentially unhindered off of the slanted outer surface of the gas collector and settles on the bottom of the basin. The usable gas arising during the subsequent conversion process rises upward and reaches the gas collector. Adjacent gas collectors advantageously have a slight overlap in this case, through which a loss of gas, which could otherwise rise upward unhindered through the intervening space to the water surface, is prevented. In this case, the downwardly moving sewage sludge may possibly slide from one outer surface onto the outer surface of an adjacent gas collector, the distance between adjacent gas collectors being dimensioned in such a way that blockage of the intermediate space is prevented. Multiple gas collectors may be positioned next to one another and in multiple planes above one another, in order to thus increase the capacity of the apparatus for three-phase separation. It has been found to be good practice to provide an angle of inclination relative to horizontal of between 50° and 70°, as a result of which both reliable sliding off of the introduced sewage sludge and also large-area, and therefore unproblematic, capture of the rising gas may be achieved simultaneously.
The gas collector is typically assembled on site from prefabricated components or from concrete or plastic, so that it is possible to achieve any desired expansion in size in one plane and/or in further planes on top of one another.
It has been found to be disadvantageous during operation of such three-phase separation apparatus that the consistency of the sewage sludge to be treated often varies greatly. As a result, the sewage sludge may adhere or build up on the outer surface of the gas collector. In order to counteract this, it is necessary to previously investigate and possibly pre-treat the sewage sludge, which results in undesirably high treatment costs. If blockage of the intermediate spaces nonetheless occurs, then a costly manual cleaning is necessary.